The subject matter of the present invention comprises a method for simultaneously permanent shaping of hair, especially of natural hair and dyed hair, and dyeing the hair and/or hair color renewing. In a first step of this method the hair swells and its natural pH is changed and at the same time the disulfide bridge bonds of the hair are opened and the dyestuffs for the hair are applied to the hair. In a second step the disulfide bridges are closed again by a reforming treatment and the dyestuffs on the hair are oxidatively developed.
The classical technique for performing the permanent hair shaping consists in that in a first step the disulfide bonds of the hair keratin are opened with the help of an agent, which contains an effective reducing ingredient, and subsequently the disulfide bonds are again reformed using a fixing composition containing an oxidizing agent. Suitable reducing agents include sulfites, thioglycolic acid, thiolactic acid, 3-mercaptopropionic acid, mercaptocarboxylic acid esters and cysteine. These reducing agents are either acidic (sulfite, bisulfite and mercaptocarboxylic acid esters) or alkaline (alkali and ammonium salts of mercaptocarboxylic acids). In the case of alkali-adjusted shaping agents the required alkalinity is obtained, above all, by addition of ammonia, organic amines, ammonium or alkali carbonates and ammonium or alkali hydrogen carbonate. Especially hydrogen peroxide-containing or bromate-containing liquids can be used as the fixing agent.
Permanent shaping of human hair generally takes place, when the washed and hand towel dried hair is first divided into several parts and these parts are then wound on curlers.
After finishing winding the hair on the curlers the curlers are thoroughly moistened with the required amount of permanent shaping composition. The curlers used for the permanent shaping have a diameter of about 5 to 13 millimeters, while curlers for hair curling have a diameter of over 13 millimeters.
The acting time of the permanent shaping composition during a permanent treatment depends on the desired degree of reforming of the disulfide bonds and the condition of the hair, and amounts to about 3 to 30 minutes. Heating the hair, for example using a radiant heater or a drying hood, may shorten the acting time.
After expiration of the required acting time of the permanent shaping composition, the hair is rinsed with water and treated with a fixing agent, for example an aqueous solution of hydrogen peroxide or potassium bromate. The acting time of the fixing composition usually amounts to about 1 to 30 minutes. Subsequently the curlers are removed, if necessary the hair is still after-treated with the fixing agent for a few minutes and then rinsed with water, put in a hairstyle and dried.
Frequently however dyeing or tinting the hair is desired as well as a permanent shaping of the hair. Especially the hair looses a large part of its color and its luster during a permanent wave treatment. A special dyeing process is then required after the permanent shaping of the hair. However in the case of an oxidative dyeing this leads to excessive stress of the hair, since each oxidative dyeing of the hair or permanent shaping treatment acts aggressively on the hair structure. Dyeing or tinting is not uniform over the entire hair length according to the differences in hair structure. The permanence of the dyeing is only guaranteed for a short time, since after a few hair washings the dye is washed out from the hair. This leads to a lengthening of the entire treatment process.
A reduction in the structural stress on the hair and an improvement of the permanence of the hair dyeing can be achieved by simultaneously performing the hair shaping and dyeing treatment. A combination of both treatments of this type would also save time.
There have already been many attempts to provide methods for simultaneously performing permanent shaping of hair and dyeing of hair. For example, such methods are disclosed in DE-AS 1 129 261 and GB-PS 876 663. These prior art methods permit simultaneous permanent shaping and dyeing of hair, including white and gray hair. These methods are based on a permanent shaping composition, which comprises an aqueous solution of a keratin-reducing agent and a suitable basic dye precursor compound. The dye precursor compound is in the form of a stable leuko-compound, for example Crystal violet, Methylene blue, Fuchsine or Malachite green, and is converted with a subsequently applied oxidative fixing agent to the actual dyestuff that acts on the hair.
The possibility of simultaneously dyeing and permanent shaping of the hair by addition of oxidation dye precursor compounds to an alkaline thioglycolate solution is discussed in the review article “Permanent Shaping and Hair Dyeing in One Working Process {Dauerwellen und Haarfärben in einem Arbeitsgang}”, by R. Heilingötter, in Cosmetic-Perfume-Drugs Review {Kosmetik-Parfüm-Drogen Rundschau} 3/4 (1965), pp. 35-36. Finally a method for permanent shaping and simultaneously dyeing of hair is described in EP-B 0 352 375. In this latter method the hair is first treated with a first composition. This first composition contains from 0.1 to 6 percent by weight of thioglycolate and 3 to 10 percent by weight of cysteine as keratin-reducing agent, from 0.01 to 4 percent by weight of para-phenylenediamine and/or ortho-phenylenediamine and from 0.01 to 1 percent by weight of resorcinol as oxidation dye precursor compounds. The first composition also contains from 0.01 to 1 percent by weight of antioxidant, from 0.01 to 1 percent by weight heavy metal complexing agent, from 0.01 to 1 percent by weight surfactant and an alkalizing agent for adjustment of the pH to from 9.0 to 9.5. After that a second composition containing from 3 to 8 percent by weight of hydrogen peroxide is applied to the hair without rinsing the previous first composition from the hair.
However all currently known methods for permanent shaping of hair and simultaneous dyeing or tinting of hair have the disadvantage that the results obtained are not always satisfactory. Several of the dyestuffs, for example certain oxidation hair dye compounds, which are employed in these methods, are unstable in the strongly reducing thioglycolate solution. They react reductively during extended storage and their dyeing power is lost so that the making of commercial preparations is impossible. Also the red shades of special interest are not satisfactorily obtained with these dye compounds. Other dyestuffs used in methods of simultaneously dyeing and permanent shaping, for example the dyestuffs described in DE-AS 1 129 261 and GB-PS 876 663, provide dyed hair colors with only an insufficient light fastness.
Conventional permanent shaping methods especially cause a significant color loss, especially for dyed hair. Permanently waved natural hair notably looses its luster and is partially bleached by the treatment. Because of that the hair colors are dull and feeble.